Stabilized olefin polymers

Abstract

An ultraviolet stabilizer for olefin polymers. It is a combination of a 2-hydroxyphenylbenzotriazole, a bis-(dialkylphenyl)pentaerythritol diphosphite.

I claim: 
     
       1. A polymer composition stabilized against deterioration in the presence of ultraviolet radiation comprising an olefin polymer and stabilizing amounts of (1) a hydroxyphenylbenzotriazole having the structural formula ##STR4## where R 1  is lower alkyl or halogen, R 2  is lower alkyl, halogen or hydrogen, and X is chlorine or hydrogen and (2) a bis-(dialkylphenyl)pentaerythritol diphosphite where the alkyl groups each contain 3-9 carbon atoms. 
     
     
       2. The polymer composition of claim 1 wherein the olefin polymer is a polymer of propylene. 
     
     
       3. The polymer composition of claim 1 wherein the olefin polymer is polypropylene. 
     
     
       4. The polymer composition of claim 1 wherein the alkyl groups in the bis-(dialkylphenyl)pentaerythritol diphosphite are bulky groups. 
     
     
       5. The polymer composition of claim 4 wherein the alkyl groups are tertiarybutyl groups. 
     
     
       6. The polymer composition of claim 1 wherein the bis-(dialkylphenyl)pentaerythritol diphosphite is a bis-(2,4-dialkylphenyl)pentaerythritol diphosphite. 
     
     
       7. The polymer composition of claim 1 wherein the hydroxyphenylbenzotriazole is 2-(2'-hydroxy-3',5'-ditertiarybutylphenyl)5-chlorobenzotriazole. 
     
     
       8. A polymer composition stabilized against deterioration in the presence of ultraviolet radiation comprising polypropylene and stabilizing amounts of (1) 2-(2'-hydroxy-3',5'-ditertiarybutylphenyl)5-chlorobenzotriazole and (2) a bis-(ditertiarybutylphenyl)pentaerythritol diphosphite.